Method and apparatus for maintaining or restoring a decreasing production from a hydrocarbon or gas well

ABSTRACT

The present invention provides a method and apparatus for maintaining or restoring decreasing production from a hydrocarbon or gas well using the exhaust of an internal combustion engine. The exhaust is utilized to displace or lighten the fluids in a well bore and increase the bottom hole pressure allowing the well to flow more easily with minimal or no damage to the formation that produces the hydrocarbon or gas. In another aspect, the present invention provides a means of purging and/or pressure testing production wells, pipelines, containers or vessels using exhaust gas. The present invention is a simple, effective, inexpensive and mobile means for maintaining or restoring a production well and/or purging and/or pressure testing of pipelines, containers or vessels.

FIELD OF THE INVENTION

The present invention relates to the oil and gas industry. The present invention more particularly relates to methods and apparatuses for maintaining or restoring a decreasing production from a gas or oil well by increasing the bottom hole pressure and/or displacing or lightening the fluids in a well bore. The present invention also relates to methods and apparatuses for purging and/or pressure testing pipelines, containers, vessels, etc.

BACKGROUND OF THE INVENTION

In gas and oil fields, a well often exhibits a decreasing production of hydrocarbon fluid and/or gas over time. This is attributed to decreasing bottom hole pressure as well as the presence of water in the formation. Many hydrocarbon and natural gas producing wells generate water from the same formation that produces the hydrocarbon or gas. In wells having sufficient underground pressure within the producing formation, the production fluid is lifted naturally; however, there are a significant number of wells in which the underground pressure is not sufficient to lift the production fluid to the surface.

Several techniques have been developed for increasing bottom hole pressure and/or displacing water such as downhole pumps or bottom hole lift assemblies, which require either mechanical, electrical, or hydraulic connections to the surface. Downhole pumps also require a lot of maintenance and the size of the existing well casing string may prevent the installation of a downhole pump. Thus, if the well is to remain productive, well “cleanouts” are often performed.

A technique that is often used is pumping air into the well to displace the water. The serious drawback to this approach is that the oxygen component of the air along with pressure can sometimes cause explosions.

The risk of explosion can be reduced using certain chemical agents, but these are generally costly and there are negative environmental effects. Inert gas such as Nitrogen can be used, but this can be quite expensive.

Several techniques also have been developed for purging wells, pipelines, containers, and vessels, etc., such as using inert gas to displace explosive mixtures so vessels, containers pipelines, etc., can be worked on or repaired in the same environment.

All the techniques noted above can be very expensive in one way or another. What are needed therefore are simple and inexpensive methods and apparatuses for maintaining or restoring a decreasing hydrocarbon and/or gas production by displacing or lightening fluids in the well bore and increasing bottom hole pressure. What are further needed are methods and apparatuses for purging and/or pressure testing wells, pipelines, containers, vessels etc.

SUMMARY OF THE INVENTION

In one aspect, the present invention provides a method and apparatus for maintaining or restoring decreasing production from a hydrocarbon or gas well using the exhaust of an internal combustion engine. The exhaust is utilized to displace or lighten the fluids in a well bore and increase the bottom hole pressure allowing the well to flow more easily with minimal or no damage to the formation that produces the hydrocarbon or gas.

In another aspect, the present invention relates to the purging and/or pressure testing of production wells, pipelines, containers, vessels, etc., using the exhaust of an internal combustion engine.

The exhaust exiting the internal combustion engine includes gases and substances comprising carbon monoxide and hydrocarbons. The exhaust is preferably filtered through a particulate filter which removes the hydrocarbons and combustible matter. The exhaust is also preferably run through a booster to increase flow. The exhaust is also preferably cooled to a suitable temperature before entering the exhaust inlet. Once the exhaust goes through a compressor, a corrosion inhibitor can be added. The exhaust can then be introduced into the well, pipeline, container, vessel, etc. The pressure and flow rate can be regulated at the compressor to a rate of 0 to 2500 psi and 0 to 1000 cfm per unit, for example.

The present invention advantageously provides a simple, inexpensive and mobile method for maintaining or restoring a production well and/or purging and/or pressure testing of pipelines, containers, vessels, etc. The exhaust from an internal combustion engine works well at increasing the bottom hole pressure and/or displacing or lightening fluids, and is less costly than using chemical agents or inert gases. There is also a very low risk of explosion because the exhaust contains much depleted oxygen levels and is filtered through a particulate filter which removes the hydrocarbons and combustible matter.

BRIEF DESCRIPTION OF THE DRAWINGS

A detailed description of the invention is provided by way of example only and with reference to the following drawings, in which:

FIG. 1 illustrates an apparatus in accordance with one embodiment of the present invention;

FIG. 2 illustrates apparatuses operating in parallel;

FIG. 3 a and FIG. 3 b illustrate exhaust being provided down tubing and casing, respectively, to displace or lighten formation fluids; and

FIG. 4 a and FIG. 4 b illustrate purging and/or pressure testing of a container, a vessel, and a pipeline.

In the drawings, the invention is illustrated by way of example. It is to be expressly understood that the description and drawings are only for the purpose of illustration and as an aid to understanding, and are not intended as a definition of the limits of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to the use of exhaust gas from an internal combustion engine as a means of maintaining or restoring a decreasing well production. In addition to increasing the bottom hole pressure, displacing or lightening fluids in a well bore, exhaust gas can be utilized for purging and/or pressure testing production wells, pipelines, containers, vessels, etc.

In one embodiment, the method of the present invention should be understood as comprising the steps of: (i) connecting an internal combustion engine to a wellhead; and (ii) directing the exhaust gas of the internal combustion engine to the wellhead, wherein the exhaust gas is operable to displace or lighten fluids, increase bottom hole pressure and/or purge the well.

The following optional steps may also be included. The exhaust gas can be pressure boosted by a booster to give the exhaust enough flow to sufficiently flow through the system and feed the compressor. Then the exhaust can be filtered through a particulate filter to take out the hydrocarbons and combustible matter. Next the exhaust can be cooled through exhaust coolers which have glycol running through them, for example. The glycol is then cooled in radiators with fans cooling the radiator. The cooling of the exhaust is important because after the exhaust is cooled it goes to a compressor, and compressors generally are not operable to handle gases at elevated temperatures. Once the exhaust gets to the compressor, the exhaust is regulated and controlled, i.e. pressure and flow. The exhaust can also be injected with a corrosion inhibiter to prevent corrosion of anything the exhaust is pumped into, such as the wellhead or a vessel.

According to one aspect of the present invention, the exhaust can be pumped to a wellhead which in turn is pumped down the well bore (hydrocarbon or gas). When the exhaust is pumped down the well bore it displaces or lightens fluids in the well bore and increases bottom hole pressure allowing the well to flow more easily, without damaging the formation.

An example of apparatus in accordance with the present invention is best understood with reference to FIG. 1, which illustrates an exhaust unit 140. Exhaust gas comes out of the internal combustion engine 100 through light wall piping 101. An example of a suitable engine for the combustion engine 100 is a CUMMINS™ Model DSHAA 60 Hz 135 kW diesel generator. The exhaust flows into a three way valve 102 which is vacuum operated by the booster 109 and engine 100; its function is to direct the exhaust to go to either the atmosphere or to the rest of the system.

On top of the three way valve 102 there is a check valve 103, in place to ensure that no air from the atmosphere can be sucked into the system. Going to the side of the three way valve 102, the light wall piping 104 leads to another check valve 105. This check valve is in place to ensure that the exhaust from the engine 100 can flow into the system but not back into the engine 100.

From the check valve 105 the exhaust goes through the light wall piping 106, which includes a pressure safety valve 107. The pressure safety valve 107 is in place as a safety measure to prevent the light wall piping 106 and the rest of the system from building up too much pressure. The pressure safety valve 107 can be set to blow off at 20 psi, for example. The piece of light wall piping 106 that comes from the check valve 105 leads to a particulate filter 108. The particulate filter 108 filters out soot, hydrocarbons and/or combustible matter so the exhaust does not plug up or otherwise foul the other components of the exhaust unit 140.

From the particulate filter 108 the exhaust goes to a booster 109. The booster 109 is in place to boost the flow of the exhaust so the exhaust can flow through the system and supply the compressor 135 sufficiently. The three way valve 102 is controlled with vacuum lines to the engine 100 and the booster 109, such that: (i) when the engine 100 is sped up, the three way valve 102 is opened by the vacuum created; (ii) once the three way valve 102 opens, exhaust is let into the system which speeds up the booster 109; (iii) once the booster 109 speeds up, it turns the three way valve 102 to open more to the system and less to the atmosphere.

From the booster 109 a light wall piping 110 leads to an exhaust cooler 111 (for example, HEATCORE™ Model 12x12-16r-58/120). The exhaust cooler 110 can have light wall piping lines 112 with glycol in them. The glycol cools the exhaust as it runs through the exhaust cooler 111. The glycol filled lines 112 lead to a radiator 113 which is cooled by a fan 114, which in turn cools the glycol.

From the exhaust cooler 111, the exhaust flows through light wall piping 115 to a three way valve 119. In the light wall piping 115 there is a pressure safety valve 116 set to blow off at 20 psi, for example, which is another safety measure to prevent the system from building up excessive pressure.

A check valve 117 prevents anything coming back through the system from the compressor 135.

A tee 118 is connected to a three way valve 119 and the bottom of the tee is connected to a bypass line 122, which is connected to a tee 121 on a compressor inlet 120. The top of the tee 121 is connected to the bottom of the three way valve 119. The three way valve 119 is manually operated its function is to direct the exhaust to go either to the atmosphere or to the compressor 135. When the engine 100 is running and exhaust is flowing through the three way valve 119 and check valve 123 is open to the atmosphere, the bypass line 122 allows the compressor 135 to be started without starving for exhaust. The check valve 123 is on top of the three way valve so no air from the atmosphere can be sucked into the system by the compressor 135.

Once the exhaust is lead into the compressor inlet 120, the compressor 135 pumps the exhaust out of the outlet and into piping 124 which leads to a tee 125. Connected to the tee 125 is a pressure safety valve 126 and a three way valve 127. The three way valve 127 directs the exhaust to go to either the atmosphere or to a high pressure hose 137, which connects to the wellhead 138. On top of the three way valve 127 is a check valve 128 which prevents air from the atmosphere from going back into the system. On the side of the three way valve 127 is a check valve 129 which stops anything coming back from the wellhead 138 and into the system.

Connected to check valve 129 is a tee 130 which is where corrosion inhibiter can be injected into the exhaust stream. A corrosion inhibiter (for example, ENCAPTRON™ 95) is generally a suitable chemical that is injected into the system as a safety measure to prevent the exhaust from corroding downstream. The corrosion inhibiter can be contained in a tank 136 and distributed by a pump 134 through piping 133, including a check valve 132, connecting to the bottom of the tee 130 which leads to the high pressure hose 137. On the side of the tee 130 is a shutoff valve 131 connected to the high pressure hose 137, which connects to the wellhead 138, or alternatively a pipeline, container, or vessel, etc

The apparatus of the present invention can be operated in the following manner. The internal combustion engine 100 is started to warm up. The three way valve 119 is turned so when the exhaust gets to the three way valve 119 it can flow up through the check valve 123 and out into the atmosphere. Next, the three way valve 127 can be turned so when the exhaust gets to it the exhaust can go out of the compressor through the check valve 128 and out to the atmosphere. The engine 100 can be idled up which will open the vacuum-activated three way valve 102, which will let the exhaust flow into the system.

The exhaust will flow to the particulate filter 108 (for example, DCL MINE-X™ Model 15x15) and into the booster 109, thereby starting the booster 109. From the booster 109, the exhaust goes to the cooler 111, and from the cooler through the check valve 117, the three way valve 119, and the check valve 123 out to the atmosphere.

Next, the compressor 135 can be started since the bypass line 122 is feeding exhaust to the compressor inlet 120. HURRICANE™ Model 903-85/2000 psi with 600 cfm capacity is an example of a suitable compressor. With the compressor 135 running, exhaust is pumped through the compressor outlet 124 and into the three way valve 127, and through the check valve 128 which is directed out to the atmosphere.

The final steps are to hook up the high pressure hose 137 to the wellhead 138 (or pipeline, container, vessel, etc.), open the shutoff valve 131, start the corrosion inhibiter pump 134, turn the three way valve 127 so the exhaust goes to the high pressure hose 137, turn the three way valve 119 so the exhaust goes to the compressor 135, and idle up the compressor 130 and engine 100 to a desired rpm to provide the exhaust to the wellhead, pipeline, container, vessel, etc., at a desired pressure.

The exhaust unit 140 can be conveniently designed as a skid unit and implemented on a flat bed truck 139, or another type of trailer, etc. The exhaust unit 140 could also be designed as a permanent unit.

The exhaust unit 140 can also be connected in parallel if a greater flow/pressure is required, as illustrated in FIG. 2. In this case, three exhaust units 140 are connected by high pressure hoses 137 to a distributing hub 142, which is connected to the wellhead 138.

FIG. 3 a illustrates exhaust being pumped down tubing of a well hole, building up bottom hole pressure and displacing or lightening fluids, and allowing the fluids to flow back up the tubing. FIG. 3 b illustrates exhaust being pumped down casing of a well hole, building up bottom hole pressure and displacing or lightening fluids, and allowing the fluids to flow back up the tubing.

In another embodiment, the method of the present invention should be understood as comprising the steps of: (i) connecting an internal combustion engine to a pipeline, container, vessel, etc.; and (ii) directing the exhaust gas of the internal combustion engine to the pipeline, container, vessel, etc., wherein the exhaust gas is operable to purge and/or pressure test the pipeline, container, vessel, etc.

FIG. 4 a illustrates purging and/or pressure testing of a container and a vessel. FIG. 4 b illustrates purging and/or pressure testing of a pipeline.

According to this embodiment, the following optional steps may also be included. The exhaust can be boosted, filtered, cooled and the pressure and flow regulated and controlled by the same means as described above. Once the exhaust goes through the booster, filter, cooler and/or compressor and the corrosion inhibiter is injected, it can be connected to one end of a pipeline. It can then be pumped through the pipeline thereby purging the line. The other end of the pipeline can be connected to a vented containment tank. The containment tank is there to contain and hold any water or sludge that may be in the line. Once the exhaust flows through the line and into the containment tank, the line will be purged and substantially free of combustible gases. The same principles are used for containers and vessels, etc. The exhaust gas is also operable to pressure test pipelines, containers, vessels, etc., wherein the exhaust gas is pumped into the pipeline, container, vessel, etc., to a desired pressure from 0-2500 psi.

It will be appreciated by those skilled in the art that other variations of the invention may also be practiced without departing from the main scope of the invention. 

What is claimed is:
 1. A method for maintaining or restoring decreasing production from a hydrocarbon or gas well comprising: (a) connecting an internal combustion engine to a wellhead associated with the well; and (b) directing exhaust gas of the internal combustion engine to the wellhead by means of a delivery apparatus connected to the wellhead, wherein the exhaust gas is operable to displace fluids and/or increase bottom hole pressure and thereby maintaining or restoring decreasing production from the well.
 2. The method of claim 1 further comprising filtering the exhaust gas prior to entering the wellhead.
 3. The method of claim 1 further comprising boosting the exhaust gas prior to entering the wellhead to increase flow.
 4. The method of claim 1 further comprising cooling the exhaust gas prior to entering the wellhead.
 5. The method of claim 1 further comprising regulating flow of the exhaust gas using a compressor.
 6. A method for purging and/or pressure testing a well, pipeline, container or vessel comprising: (a) connecting an internal combustion engine to a delivery means and connecting the delivery means to an inlet associated with the well, pipeline, container or vessel; and (b) directing exhaust gas of the internal combustion engine to the inlet, the flow of exhaust gas being operable to purge and/or pressure test the well, pipeline, container or vessel.
 7. The method of claim 6 further comprising filtering the exhaust gas prior to entering the inlet.
 8. The method of claim 6 further comprising boosting the exhaust gas to increase flow prior to entering the inlet.
 9. The method of claim 6 further comprising cooling the exhaust gas prior to entering the inlet.
 10. The method of claim 6 further comprising regulating flow of the exhaust gas using a compressor.
 11. An apparatus for maintaining or restoring decreasing production from a hydrocarbon or gas well comprising: (a) an internal combustion engine having an exhaust; and (b) a delivery means operable to be connected to a wellhead associated with the well such that a flow of exhaust gas is directed into the well, the flow of exhaust gas being operable to displace fluids and/or increase bottom hole pressure and thereby maintaining or restoring decreasing production from the well.
 12. The apparatus of claim 11 further comprising a filter operable to filter the exhaust gas.
 13. The apparatus of claim 11 further comprising a booster operable to the flow of the exhaust gas.
 14. The apparatus of claim 11 further comprising a cooling means operable to cool the exhaust gas.
 15. The apparatus of claim 11 further comprising a compressor operable to regulate the flow of the exhaust gas.
 16. An apparatus for purging and/or pressure testing a well, pipeline, container or vessel comprising: (a) an internal combustion engine having an exhaust; (b) a delivery means connected to the internal combustion engine, and the delivery means is connected to an inlet associated with the well, pipeline, container or vessel such that a flow of exhaust gas is directed into the well, pipeline, container or vessel, the flow of exhaust gas being operable to purge and/or pressure test the well, pipeline, container or vessel.
 17. The apparatus of claim 16 further comprising a filter operable to filter the exhaust gas.
 18. The apparatus of claim 16 further comprising a booster operable to the flow of the exhaust gas.
 19. The apparatus of claim 16 further comprising a cooling means operable to cool the exhaust gas.
 20. The apparatus of claim 16 further comprising a compressor operable to regulate the flow of the exhaust gas. 